DHCPD issue parameters

[Teva AVRIL-TEIPOARII]

Hi,


What could be done so the DHCP client would look at the changed options
during a renew of its lease ?

It really seems something like this indeed:After 2 days off, i'm trying
again, and then DNS parameters has been updated, but now client has
192.168.45.1 as primary AND secondary DNS servers, instead of 192.168.45.1
and 192.168.1.3.

I've tested different computers, and result is the same for all of them now:
every client get 192.168.45.1 as DNS servers as primary and secondary.

I could understand that one client could misbehave DHCP Offer from the DHCP
server, however when all clients has the same behavior... Really weird...

If anyone has an idea, i'd be glad to read it.

Regards,









----------------------------------------------------------------------

Message: 1
Date: Sat, 14 Apr 2012 14:32:55 +0200
From: Harald Sch?ner <harald.schoener at mygate.net>
To: Users of ISC DHCP <dhcp-users at lists.isc.org>
Subject: Re: DHCPD issue parameters
Message-ID:
	<CAKd10K-Fj_M=2JQx1KY2+o6MDR63G-OjR92f5L8DktX1z0mJFQ at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

This is a misbehavior of the DHCP client, as it doesn't look at the changed
options during a renew of its lease.

This has been observed with many dhcp clients, even the isc one.



On 13 April 2012 23:25, Teva AVRIL-TEIPOARII <teva at viti.pf> wrote:

>
> Greetings,
>
> I've got a dhcpd server, which is working good. However i've got an issue:
> i've modified one parameter on the dhcpd.conf for one subnet (i've 
> changed option domain-name-servers ip), i've restarted the dhcpd service.
>
> My issue is i've got an ip address, but not the update DNS-servers.
>
> Here below configuration of the dhcpd.conf before modification:
>
> shared-network test {
> option domain-name "test.com";
> option domain-name-servers 192.168.1.2, 192.168.1.3; 
> default-lease-time 360; max-lease-time 360;
>
> subnet 192.168.10.0 netmask 255.255.255.0 { option routers 
> 192.168.10.254; option subnet-mask 255.255.255.0; option 
> broadcast-address 192.168.10.255; }
>
> pool {
> range 192.168.10.1 192.168.10.253;
> }
> }
>
> And now after modification:
>
> shared-network test {
> option domain-name "test.com";
> option domain-name-servers 192.168.45.1, 192.168.1.3; 
> default-lease-time 360; max-lease-time 360;
>
> subnet 192.168.10.0 netmask 255.255.255.0 { option routers 
> 192.168.10.254; option subnet-mask 255.255.255.0; option 
> broadcast-address 192.168.10.255; }
>
> pool {
> range 192.168.10.1 192.168.10.253;
> }
> }
>
> And here below global parameters applied to all subnets:
>
>
> ddns-update-style none;
> authoritative;
> log-facility local7;
> update-static-leases on;
>
>
>
>
> The result is that instead of having 192.168.45.1 and 192.168.1.3 as 
> primary and secondary DNS, i still got 192.168.1.2 and 192.168.1.3 as 
> primary and secondary DNS.
>
> I've deleted dhcpd.leases , thinking that maybe the issue could come 
> from some leases not expired, but result is the same.
>
> I've performed a wireshark capture, and during the DORA process, i see 
> that the DHCP server is sending the update DNS as it should. However 
> on my PC (on Windows), i still see old DNS servers attributed 
> (attribution is automatic, it's not in static on network configuration 
> of the PC).
>
> I don't understand where this problem come from, if you have an idea, 
> please let me know.
>
>
>
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>